Comparing dopaminergic dynamics in the dorsolateral striatum between adolescent and adult rats- Effect of an acute dose of WIN55212-2

Brief summary:

A recent study has exposed an age-dependent mechanism within the dopaminergic system that relies on cannabinoid receptor 1 (CB1). Adult and adolescent dopamine levels were examined in the presence of a CB1 agonist and increased levels of extracellular dopamine were found in adolescents. This study reveals the different effects cannabis-based medicine has depended on the age of the patient and warrants future research to ensure cannabis has the desired therapeutic effect on patients.

Dr Caplan Discussion Points:

This adds a helpful layer of insight to the way an animal model of dopamine changes over time, as well as its interaction with exogenous cannabinoids. This sheds light on the natural evolution of the dopamine control system (irrespective of how it interacts with endocannabinoids), and it also points to how cannabinoids may be involved.

This helps to educate the discussion about how psychosis and cannabis use may interact. There is a long-held understanding that dopamine abnormalities in the specific parts of the brain (mesolimbic and prefrontal brain regions) exist in schizophrenia. More recently, research has also strongly suggested that other neurotransmitters, including glutamate, GABA, acetylcholine, and serotonin are also involved in schizophrenia (and, coincidentally, there is also interaction with these other neurotransmitters from various components of cannabis). Nonetheless, this study simply suggests that, by nature, basal dopamine levels increase during adolescence. Also, the study points out that some cannabinoids boost basal levels too. It seems logical to suggest that excessive dopamine may create a problematic force of additional tipping toward illness, within individuals for whom a congenital predisposition toward illness exists.

In a crossover trial of 39 patients with Alzheimer’s disease, treatment with nabilone (a synthetic THC analog) was associated with significant improvement in agitation and, remarkably, cognition. Further studies should examine the effects of both THC and CBD in patients with Alzheimer’s disease because anxiety is common in dementia and may exacerbate agitation.